Association between circulating CTRP12 levels and type 2 diabetes: A meta-analysis

Table 1 Baseline characteristics of the included studies, mean ± SD

Ref.	Country	Study design	Age (years) T2DM/control	CTRP12/adipolin assay	Sample size (T2DM/control)	CTRP12 concentration (T2DM)	CTRP12 concentration (control)	Unit
Ameer et al[15], 2021	Iraq	Case-control study	35-60	ELISA	72 (54/18)	1.32 ± 0.48	1.64 ± 0.73	ng/mL
Bai et al[16], 2017	China	Cross-sectional study	51 ± 11.85/49 ± 11.11	ELISA	262 (124/138)	0.446.8 ± 87.92	808.5 ± 102.66	pg/mL
Liu et al[17], 2025	China	Case-control study	65.67 ± 3.29/66.02 ± 3.34	ELISA	278 (139/139)	2.7 ± 0.79	4.03 ± 1.14	ng/mL
Du et al[13], 2020	China	Case-control study	55.79 ± 10.06/49.32 ± 8.3	ELISA	169 (115/54)	424.14 ± 211.35	555.83 ± 244.23	pg/mL
Guo et al[18], 2021	China	Cross-sectional study	54.66 ± 9.61/52.73 ± 9.94	ELISA	231 (161/70)	2.36 ± 1.2	3.97 ± 1.22	ng/mL
Han et al[19], 2020	China	Case-control study	54 ± 7.42/51 ± 8.0	ELISA	83 (56/27)	392.3 ± 150.57	660.53 ± 160.51	pg/mL
Gorgani-Firuzjaee and Khodabandehloo[20], 2020	Iran	Case-control study	55.95 ± 1.97/46.44 ± 1.25	ELISA	60 (30/30)	167.36 ± 33	391.96 ± 91	pg/mL
Ligade et al[21], 2023	India	Cross-sectional study	20-50	ELISA	30 (20/10)	5.91 ± 4.36	7.68 ± 6.5	ng/mL
Yang et al[22], 2025	China	Case-control study	54.35 ± 8.07/54.54 ± 8.27	ELISA	196 (156/40)	2.68 ± 0.89	4.18 ± 1.14	ng/mL
Zhang and Huang[23], 2025	China	Case-control study	-	ELISA	250 (200/50)	2.17 ± 0.99	4.13 ± 1.25	ng/mL
Liu et al[24], 2025	China	Case-control study	-	ELISA	174 (116/58)	0.52 ± 0.13	0.91 ± 0.13	ng/mL
Sun et al[25], 2024	China	Case-control study	66.04 ± 3.91/66.11 ± 3.82	ELISA	298 (198/100)	478.58 ± 155.45	717.89 ± 244.4	pg/mL
Liu et al[26], 2019	China	Case-control study	47.29 ± 12.82/45.23 ± 13.23	ELISA	90 (60/30)	4.12 ± 1.45	6.84 ± 1.09	ng/mL

T2DM: Type 2 diabetes mellitus; CTRP12: C1q/TNF-related protein 12; ELISA: Enzyme-linked immunosorbent assay.

Table 2 Quality assessment of included studies using the Newcastle-Ottawa Scale

Ref.	Selection (max 4)	Comparability (max 2)	Outcome (max 3)	Total score (0-9)
Ameer et al[15], 2021	2	2	1	5
Bai et al[16], 2017	3	2	2	7
Liu et al[17], 2025	2	1	3	6
Du et al[13], 2020	4	2	2	8
Guo et al[18], 2021	4	2	2	8
Han et al[19], 2020	3	2	2	7
Gorgani-Firuzjaee and Khodabandehloo[20], 2020	3	2	3	8
Ligade et al[21], 2023	4	1	3	8
Yang et al[22], 2025	4	2	3	9
Zhang and Huang[23], 2025	4	2	2	8
Liu et al[24], 2025	4	2	3	9
Sun et al[25], 2024	3	2	3	8
Liu et al[26], 2019	3	2	2	7

Table 3 The results of subgroup analysis

Subgroup	Number of comparisons	Participants	SMD (95%CI)	Z value	P value	Test of heterogeneity
						I2 (%)	P value
Overall	13	2193	-1.73 (-2.22 to -1.25)	-	-	-	-
FBG	10	1813				0	0.65
7.0-10.0 mmol/L	8	1640	-2.05 (-2.76 to -1.35)	5.7	< 0.00001	97	< 0.00001
> 10.0 mmol/L	2	173	-1.87 (-2.24 to 1.49)	9.74	< 0.00001	0	0.46
FINS	8	1346	-	-	-	0	0.71
≤ 10 μU/mL	4	826	-2.17 (-3.24 to -1.10)	3.99	< 0.00001	97	< 0.00001
> 10 μU/mL	4	520	-2.42 (-3.21 to -1.63)	6.01	< 0.00001	90	< 0.00001
HOMA-IR	9	1644	-	-	-	78.5	0.03
≥ 3.0	7	1330	-2.37 (-3.10 to -1.64)	6.35	< 0.00001	96	< 0.00001
< 3.0	2	314	-1.47 (-1.84 to 1.10)	7.78	< 0.00001	38	0.21
HbA1c	10	1581	-	-	-	0	0.56
< 8.0%	4	619	-1.50 (-2.18 to -0.82)	4.31	< 0.00001	90	< 0.00001
≥ 8.0%	6	962	-1.79 (-2.45 to -1.12)	5.26	< 0.00001	94	< 0.00001
Age	9	1667	-	-	-	7.2	0.3
≤ 55	5	862	-2.08 (-2.99 to -1.17)	4.48	< 0.00001	96	< 0.00001
> 55	4	805	-1.50 (-2.12 to -0.87)	4.69	< 0.00001	93	< 0.00001
BMI	10	1813	-	-	-	91.6	< 0.00001
Normal	1	298	-1.26 (-1.52 to -1.00)	9.44	< 0.00001	-	-
Overweight	8	1455	-1.98 (-2.68 to -1.27)	5.5	< 0.00001	96	< 0.00001
Obese	1	60	-3.24 (-4.02 to -2.45)	8.09	-	-	-
TG	10	1813	-	-	-	60.6	0.11
< 1.7 mmol/L	3	632	-2.77 (-4.08 to -1.47)	4.16	< 0.00001	97	< 0.00001
≥ 1.7 mmol/L	7	1181	-1.65 (-2.11 to -1.19)	7.01	< 0.00001	90	< 0.00001
TC	10	1813	-	-	-	0	0.39
< 5.2 mmol/L	7	1172	-2.20 (-2.88 to -1.51)	6.30	< 0.00001	94	< 0.00001
≥ 5.2 mmol/L	3	641	-1.60 (-2.77 to -0.43)	2.68	< 0.00001	97	< 0.00001
LDL-C	9	1723	-	-	-	0	0.69
< 3 mmol/L	5	820	-1.85 (-2.30 to -1.41)	8.17	< 0.00001	81	< 0.00001
≥ 3 mmol/L	4	903	-2.14 (-3.51 to -0.77)	3.06	< 0.00001	98	0.002
HDL-C	10	1813	-	-	-	62	0.10
< 1.0 mmol/L	2	381	-1.43 (-1.88 to -0.99)	6.30	< 0.00001	59	< 0.00001
≥ 1.0 mmol/L	8	1432	-2.15 (-2.90 to -1.41)	5.65	< 0.00001	96	< 0.00001
Year	13	2193	-	-	-	71.7	0.06
≤ 2020	6	838	-2.38 (-3.49 to -1.26)	4.18	< 0.00001	97	< 0.00001
> 2020	7	1355	-1.27 (-1.55 to -0.99)	8.95	< 0.00001	76	< 0.00001
Race	13	2193	-	-	-	0	0.61
Chinese	10	2031	-1.84 (-2.36 to -1.31)	6.82	< 0.00001	95	< 0.00001
Non-Chinese	3	162	-1.37 (-3.06 to -0.32)	1.59	0.11	94	< 0.00001

SMD: Standardized mean difference; CI: Confidence interval; FPG: Fasting plasma glucose; FINS: Fasting insulin; HOMA-IR: Homeostatic model assessment-insulin resistance; HbA1c: Hemoglobin a1c; BMI: Body mass index; TG: Triglycerides; TC: Total cholesterol; LDL-C: Low-density lipoprotein cholesterol; HDL-C: High-density lipoprotein cholesterol.